This invention relates to circuitry adapted for use with image display equipment of ultrasonic scanning apparatus to facilitate puncturing of a body by a puncturing device associated with such scanning apparatus.
In the prior art a whole series of equipment is already known which is intended to facilitate piercing by a puncturing cannula of an organ or vessel aimed at in an arcuate manner with fine needle puncturing. The majority function with the aid of ultrasound. Thus, for example, U.S. Pat. No. 3,721,227 discloses a sound head with a central bore hole which acts as a guiding aid for a puncturing cannula. However, this puncturing device does not allow any puncture control in the real time echo image. On the contrary, provision is made for such control in the case of an ultrasonic applicator having a central, oblique slit location as is described, for example, in U.S. Pat. No. 4,029,084. However, the guiding bore opens into the row of ultrasonic transducer elements; since at least the central transducer element must be recessed, this can result in losses of sensitivity in the center. A further possibility for aiding puncturing is disclosed in U.S. Pat. No. 3,556,079, or even in German Patent No. 21 48 700. However, here, puncturing is limited to vessels or organs having blood flowing through them so that the ultrasonic Doppler technique is used as an aid without sectional image synthesis. Therefore, in these cases, the piercing process is closed to observation in the real-time image. A further puncturing possibility is known from the Lancet journal dated Feb. 21, 1960, page 35. Here, a scale is placed on the surface of the body within which an organ, vessel or the like is to be punctured by way of control in an x-ray image, the scale having, at one end, an aid for guiding a puncturing cannula which is inclined at a certain angle. The piercing direction can then be determined by displacing the scale at the intervals which can be taken from the display image with a prescribed angle.
U.S. Pat. No. 4,058,114 describes puncturing apparatus which comprises a guiding aid for a puncturing cannula, which is arranged to the side of an ultrasonic applicator. Also, there is mounted on a display unit, likewise to the side, a mechanical target pin which is adjustable for aiming at a puncturing area in the echo sectional image on the image screen of the display unit. The target angle of the target pin can be transferred as a piercing angle as an aid for introducing the puncturing cannula. The entire arrangement has the particular advantage that, using real-time control in the ultrasonic echo sectional image, it is also possible for piercing to take place to the side of the actual bearing surface of the ultrasonic applicator. Less advantageous, however, is the fact that a corresponding mechanical assembly is also required as a target aid on the display unit itself; this is relatively bulky and, moreover, in terms of adjustment, is time-consuming and complicated.